The present invention relates to a particle fallout/activity sensor which can monitor particle fallout in an area over a period of time at specified intervals, and store the fallout data in memory for later recall and analysis.
Detection and measurement of particle fallout, e.g. dust, fibers, etc., onto sensitive payload components is an ongoing part of payload processing at the Kennedy Space Center. At present, an indication of the amount and type of particle contamination is achieved by the use of witness plates. These plates are placed at selected locations around payload components and left for a period of time to collect fallout. The plates are then removed to a laboratory and examined under a microscope to determine and tabulate the amount and types of particles that have accumulated. This approach has the benefit of allowing a trained operator to examine the dust visually and provide an accurate analysis, but is time consuming and provides no indication of when contamination occurs. Unfortunately, the risk of payload damage from undetected contamination events is a very real possibility and the witness plate approach does not allow potentially destructive contamination events to be detected since it restricts fallout measurements to an accumulated account over an extended period of time.
A need therefore exists for a particle fallout monitoring system which provides information not only on the amount of particle fallout occurring over a predetermined time interval, but also information on the time at which the particle fallout occurs.